Answer to Question #49368 in Molecular Biology for Kevin Ko

Why do animals with millions of cells &quot;need&quot; a circulatory system while animals with few cells can do without one?

Expert's answer

2014-11-26T05:18:46-0500

Animals which consist of few cells have a capacityto transport the nutrients by cell interactions and diffusion. The maximumdistance of the last one is around 0.1 mm. So it is not enough to supply allcells quickly in the multicellular organism without specific proteins carriersand a circulatory system as a result.&nbsp;